If I understand right, I think you might be able to use the existing
replace functions in clojure.walk. I find that this is about twice as fast:
(time
(dotimes
[_ 100000]
(walk/postwalk-replace
{"exp_1" 100 "exp_2" 20 "exp_3" 5}
[:DIV [:ADD [:ID "P1" "exp_1"] [:ID "P2" "exp_2"] "exp_2419"] [:ID
"P3" "exp_3"] "exp_2418"])))
Jony
On Wednesday, 3 December 2014 18:49:01 UTC, Dmitriy Morozov wrote:
>
> Hi, guys!
>
> I have an issue with my function where I use zippers to modify data
> structure. The function modifies a tree (parsed grammar tree) to replace
> expressions with values from a given map. Sadly, the algorithm I came up
> with is pretty slow. I would appreciate if anyone can give me a hint on
> what would be the right approach to do what I'm trying to accomplish.
> Thanks!
>
> (defn- transform-values [parse-tree values-map]
> "Replaces all expressions in parsed tree with values from a given map."
> (loop [loc (zip/vector-zip parse-tree)]
> (if (zip/end? loc)
> (zip/root loc)
> (if (zip/branch? loc)
> (let [id (last (zip/children loc))]
> (if (contains? values-map id)
> (recur (zip/next (zip/replace loc (zip/node [(get
> values-map id)]))))
> (recur (zip/next (zip/edit loc #(into [] (butlast %)))))))
> (recur (zip/next loc)))
> )))
> (time
> (dotimes
> [_ 100000]
> (transform-values
> [:DIV [:ADD [:ID "P1" "exp_1"] [:ID "P2" "exp_2"] "exp_2419"] [:ID "P3"
> "exp_3"] "exp_2418"]
> {"exp_1" 100 "exp_2" 20 "exp_3" 5})))
>
> "Elapsed time: 2317.491 msecs"
>
>
>
>
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